Method of producing a seamless tubular surgical appliance



Oct. 1, 1957 P. VIRCHAUX 2,

METHOD OF PRDDUCING A SEAMLESS TUBULAR SURGICAL APPLIANCE Filed Feb. 10, 1954 Marc: 6

METHOD OF PRODUCING A SEAMLESS TUBULAR SURGICAL APPLIANCE Paul Virchaux, Saint-Blaise, Switzerland Application February 10, 1954, Serial No. 409,466. Claims priority, application Switzerland June 4, 1953 1 Claim. (Cl. 66-184) States Patie Q This invention relates to surgical appliances such as It has'been customary to form surgical appliances of the kinds above noted of ribbed knit fabric, and to lay strands of rubber in each of the courses of stitches of which the fabric is composed, with the rubber disposed between the stitch wales drawn to one face of the ribbed fabric and the stitch wales drawn to the opposite face of the ribbed fabric. Such articles have been of a more or less stiff, harsh, heavy, bulky nature, and when worn under modern silk hosiery, for example, are extremely conspicuous. Furthermore, the bulkiness and harshness of the fabric causes chafing of the skin at the places where the encased portion of the anatomy and the article are required to bend, such as the back of the knee, the front of the elbow, the instep, etc.

Modern methods of manufacture of rubber filaments, such as are employed in elastic fabrics, have made it possible to produce the rubber filaments with cross sectional areas sufficiently small to permit the filaments to be formed into relatively fine gage knitted stitches.

Prior to the invention it has also been customary to form surgical appliances of the kinds above noted on circular machines. The knit articles hitherto obtained on these machines have the advantage of being devoid of a longitudinal seam, but also the big disadvantage that they have a cylindrical form. For this reason they had to be subjected to treatments such as ironing, steamironing or steam-pressing for the purpose of giving them a shape or fashion more accurately conformed to that of a human leg. A shape or fashion obtained in this manner soon disappears during wearing and certainly during washing. Furthermore, ifthe appliance is an elastic stocking, for example, the pressure applied to the leg should have its maximum value at the ankle and progressively decrease towards the knee. This requisite is not achieved by stockings knit and treated in the manner recited above; on the contrary, a lesser tension is applied to the ankle than to the calf of the leg. Hitherto said requisite could only be attained with stockings knitted as a flat fabric on machines having two rectilinear banks of needles in parallel spaced relation to each other, and subsequently formed to a tubular structure having a longitudinal seam. However, just this seam is highly unwished and unsatisfactory to such degree that many people prefer the cylindrically knit stockings.

The main object of the present invention, therefore, is to produce a seamless elastic stocking or similar tubular appliance and to give it an anatomic form or fashion right during knitting. This is achieved, when knitting the stocking or similar appliance on a circular machine to which a. rubber bearing thread is fed with tension, 'by continually augmenting the feeding tension of the yarn for correspondingly decreasing the width and/or diminishing the feeding tension of the yarn for correspondingly increasing the width where required.

The invention will be more fully described hereinafter by way of example, reference being had to the accompanying drawing.

The single figure is an elevational, rather diagrammatic view of an elastic stocking according to the invention.

In its uppermost section or length, extending from a to b, the stocking represented on the drawing is composed of a plurality of interknit courses of similar stitches diagrammatically shown at 1. These stitches are relatively loose, What is due to the fact that during the'knitting of this cylindrical section or length a rubber bearing yarn is fed with a small tension to the cylindrical machine on which the stocking is being knit. The machine per se may be any appropriate circular knitting machine hitherto used for producing the kind of work referred to in this description. The term rubber bearing yarn means 'an elastic (rubber) filament covered, in the present instance spirally, with a textile filament of silk, cotton, woo nylon, etc. Thus, knitting this section or length from'a to b is made quite as usual.

In the interknit courses from b to c, the stitches 2 are still of the same kind as in the sections a to b, but their size continually grows less. This diminution of size can be observed in each particular course as well as when comparing successive stitches in one particular Wale line. It is obtained by continually augmenting the tension with which the rubber bearing yarn is fed to the needles of the circular machine. It may easily be realized that while such change of the feeding tension of the yarn may be effected by hand, it is desirable to carry it out by means of adequate machinery.

When continuing and knitting the courses from c to d, the feeding tension is held at a constant value, viz.: the value of the tension which is reached when knitting the last course of stitches of the section b to 0. Thus, the section or length from c to d is again knit in the usual manner.

When knitting the section or length extending from d to e the tension at which the yarn is fed to the circular machine is augmented at a rate somewhat greater than during the knitting of the section b to c with the effect that the conicity of this section d to e is accordingly stronger than that of the section b to 0 because the size of the stitches decreases more rapidly. The stitches 3 in the last course of the section a to e (or the first course of the section e to 1) have the smallest size.

In the further course of the work, when knitting the section from 2 to f, the tension with which the yarn is fed to the circular machine is continually diminished at a rate considerably greater than the rate at which it was augmented when knitting the section a to e, with the effect that this section e to f has a conicity considerably greater than, and opposed to, that of section d to e. The size of the stitches increases accordingly.

Subsequently the heel portion 4 is obtained in the usual manner by reciprocating the knitting cylinder. During that Work, the feeding of rubber bearingyarn is preferably interrupted in the known manner and replaced by a feeding of unelastic yarn such as cotton, nylon; it is taken up again for knitting the foot portion 6. When knitting this foot portion 6, the feeding tension of the rubber bearing yarn is held constant for knitting the M s, 2,807,946 v r courses in the section g to h, but somewhat augmented when knitting the courses of the section h to i, with the effect that the size of the stitches decreases from that of stitches 8 to that of the stitches 9. Finally, the end portion 7 from i to k is knit in stitches usual for such end portions. i

It should be noted that the stitches of the foot portion 6 may be of another kind than those of the leg portionv 5 (e. g.: plain instead of purl), asis'usual in elastic stockings and in the common stockings. The invention is not concerned with the kind of stitches which might change at any place in any desired manner (though normally such change does not occur during the knitting of the leg portion 5 nor during the knitting of the foot portion 6 except the border 7).

It is obvious that the width of the stocking is proportional to the even size of the stitches, in the cylindrical sections a to b, c to d and g to h, and to the mean size of the'stitches constituting one particular course, in the sections b to c, d to e, e to f and h to i.

It is also obvious that if a fashion is to be obtained which is different to that shown'in the drawing-or if another surgical appliance, such as an ankle, knee or elbow brace is to be manufactured, the number and sequence of the sections and their conicity may be changed at will. A cylindrical section mightfor example be provided between the sections d to e and e to f, by holding the feeding tension of the rubber bearing yarn at the value to which it has been increased when knitting the course of stitches 3.

The sections referred to as conical sections may have a shape slightly different of that of a cone, since the rate at which the feeding tension is augmented or diminished during the knitting of such sections need not be constant.

What I claim is:

A method of producing a full fashioned seamless tubular surgical appliance upon a circular knitting machine characterized by having fine gage knitted stitches of rubber bearing yarn comprising the step of feeding with a tension a rubber bearing yarn in the formation of successively outer knit courses and varying the said tension on said yarn during the knitting of said courses to fashion said appliance, the feeding tension on said yarn being continually augmented during the knitting of consecutive courses for the purpose of producing a length of fabric the width of which decreases while the courses are knit, and the feeding tension on said yarn being continuously diminishing at another time during the knitting of consecutive courses for the purpose of producing a length of fabric the width of which increases While the courses are knit, whereby in the knitting of an elastic stocking areas of consecutive knitted courses progressing downwardly from the top of the stocking toward the heel and toe have conicity conforming to desired anatomic form and stitch sizes are minimum in areas of desired maximum restriction upon the anatomy, as at the ankle.

References Cited in the file of this patent UNITED STATES PATENTS 2,217,225 Lawson et al. Oct. 8, 1940 2,251,533 Thurston et at. Aug. 5, 1941 2,300,808 Reed Nov. 3, 1942 2,555,974 Katterman June 5, 1951 2,672,139 Caspar Mar. 16, 1954 2,699,055 Katterman Jan. 11, 1955 FOREIGN PATENTS 342,297 Great Britain Jan. 26, 1931 

